Coating apparatus



,1 M u m w n f f RA M.. wm. n -H f IJ l\llrl lfiur 4 p M u g 0 AWV. w me .f a m y f MJ si... www.. .a 2 "d w m ...u m-. Fb. 7. 0 m v, 0 f l K Nu lhlwlflulnllniiliuiivmlnu wm w m w M d 1 G m 2. C A y u M. G n P m d uu pM/ww E 2. M. l |||||1|||||frl\ 3W' man Jan. 13, 1942. G. P. McGRAw YcoATING APPARATUS 2 Sheets-Sheet 2 Filed May 2, 1940 Patented Jan. 13,l1942 UNITED STATES PATENT ori-ICE George P. assis-nor toW externElectric Company, Incorporated.

New York, N. Y., a corporation of New York application my z, im. seranNo. :sans 9 claim. (ci. 91s5i This invention relates to coatingapparatus, and more particularly to apparatus for coating articles by adipping process.

In coating articles with paint, lacquer and other liquid materials itisoften desirable to employ a dipping process because of the inherentspeed and economy of these procedures. Processes oi' this general typehave been used for coating various articles, but the former methods andapparatus are not very suitable for use with .articles of irregularconfiguration, particularly those having perforations and surfaceindentations therein. When Vsuch articles are dip coated bythe usualprocedures. the coating medium tends to skin over the perforations andto accumulate in drips and runs at the irregular portions of the articlesurface., Consequently, it has been necessary in many cases to employsupplementary and expensive processing operations to remove the excesscoating material before it has an opportunity to dry in order to providea finish oi' satisfactory appearance and utility.

An object of this invention is the provision of improved apparatus ioryapplying a smooth, uniform and durable coating of paint, lacquer or thelike on articles of irregular configuration.

In one embodiment oi the invention, apparatus is provided for applying asmooth and uniform coating of lacquer on articles having a iiangedperiphery and a body portion with a series of indentations andperforations formed therein. The articles, suspended from a conveyor,are rst immersed in a tank of lacquer and then conducted past a seriesofshaped hot a sheet of absorbent material to remove the ac- Y cumulatedlacquer, after which the article is carried successively through heatedand cooled arcas to complete the coating operation and iinally deliveredto an unloading position.

Following is a more detailed description of the invention, taken inconjunction with the appended drawings, in which Fig. 1 is a sideelevation, partly in section, of an article coating apparatus embodyingcertain features of the invention;

Fig. 2 is an enlarged sectional view of the apparatus of Fig. 1 taken onthe line 2--2 to show portions or the apparatus and the articles undertreatment at one stage of the coating cycle;

Fig. -3 is an enlarged sectional view of .the apparatus taken on thesame line as Fig. `2 to show portions vof the apparatus and articles atasubsequent stage of thevarticle'coating cycle to that illustrated inFig. 2:

Fig. 4 is a sectional view 'oi' Fig. 2.taken on the line 4 4. and

Fig. 5 is a sectional view of Fig. 3, taken on the line I-l.

The apparatus shown in the drawings is especially adapted for coatingconiigured articles containing perforations, recesses and surfaceindentations. The particular article I illustrated in the drawings isa-base plate used on telephone subscriber sets. This base (Fig. 4) has aanged periphery il, and a body portion with a series oi periorations I2and indentations I3 ci various shapes formed therein.

The coating apparatus (Fig. l) is supported on a base or iloor il andcomprises a cabinet I which is made of sheet metal and suitably framedwith structural members to impart the necessary rigidity thereto. 'Ihecabinet, which is rectanguiar in pian section, has a back wall I6 whichslopes inwardly at its upper portion, a rooi' il, a front wall Il andside walls I9. In the front wall is a large opening at a suitable heightabove the iioor to enable the operator to load and remove the articlesconveniently.'

In the upper iront portion o! the cabinet is an exhaust duct or passage2| formed by a sloping partition 22 extending between the side walls,and a bottom wall 24 extending from the partition to the iront wall ofthe cabinet. In the partition 22 are a plurality oi' manually operatedhinged dampers 2l. The top portion of the exhaust chamber is connectedto an exhaust ian (not shown).

In the central part of the cabinet is another partition extendingbetween and secured to the side walls. This partition includes astraight front wall 25 parallel to the iront cabinet wall, a back wall26, a top 21 and a. bottom 28. The top' and bottom slope sharply fromthe front wall to the back wall of the partition thus formingcooperatively with the cabinet walls an elongated article treatingchamber extending around the cabinet.

A conveyor is provided for conducting the articles through this chamber.A series of sprocket wheels 30 are supported in bearings 3l mountacontinuous linked chain 32, One sprocket wheel in each series is drivenby keying the lower sprocket wheel in each series or set on a commonshaft extending across the cabinet and connecting the shaft to asuitable motor (not shown) The articles to be coated are supported fromthe linked chains by means of rods 33 (Fig. 2) mounted on the chains atuniform. intervals along the chain length. These rods extend betweenthe'twno chains and are secured thereto. On each end portion of eachrod, adjacent to the chains, a ball or roller bearing 34 is mounted. Anangle member 35 is supported on the outer race of the two bearings bymeans of connecting arms 36 and a series of spaced article supportinghooks 31 depend from the angle member. When the driven chains carry thearticles around the chamber, the article supporting angles move readilyon the ball bearings so that the 'position of the articles is notaffected by turning of the rod during travel of the chain around the`chamber. Y

Inith'e base fof the cabinet (Fig. 1) below the bottom sprockets is acontainer 3B for the lacquer, A paint or other coating material 39 inwhich the art-iclesare immersed. This container is mounted on wheels 40and the container is placed in the cabinet or removed therefrom forrefilling or` 1 cleaning through a hinged door 4I in each of the sidecabinet walls. r

Directly above the rear portion of the container is a-sloping drainboard 42 for returning to the container coating material that drips fromthe freshly dipped articles.

Above the drain -board and extending across the' back of the cabinetjust below the path of the articles on the conveyor is a shaped sheetmetal pipe 43, one end of -which is connected with A a hot air supplyline 44 outside of the cabinet.

Extending from the front portion of the pipe 43 vare a series of shapedand vented ducts 45 for applying hot air against the surfaces of the wetarticles. One duct is positioned between the path taken by each pair ofarticles and one duct is positioned at each end of the article series(Figs.

2 and 4). These ducts are narrow with parallel side walls ofsubstantially triangular shape. A slopingfvent 46 is cut in the lowerportion of each side wall andA additional vents 41 are provided in thefront or forward wall of each duct. When the wet articles are carried bythe conveyor into the zone of these ducts, hot air emitted from thefront vents` 41 initially sweeps across the article surfaces. Thisaction smooths the coatings as the larticle travels in an upwardlydirection against the air currents and also removescoating material fromthe perforations and indentations in the article surface. The excesscoating is thus transferred to the lower portion of the article andcollects in a pool within the bottom article flange. Then as the articleis advanced in a substantially horizontal direction by ther conveyor`air emitted from the side wall jets 45 forces this coating accumulationout over the flange to form in a bead depending from the lower outsidearticle corner or edge.

This accumulatedbead of coating material is removed by wiping or rollingthe article edge against a sheet of absorbent material 48 which ispartially wrapped around a roller 49 mounted parallel to and in back ofthe hot air ducts. Various absorbent materials. such as cloth or paper,are suitable for this purpose, but paper is used preferably for costconsiderations. The roller 49 is freely mounted in a pair of bearings5Fl. one bearing being supported on the outside of each of the sidecabinet walls. Each bearing is supported on two bolts 5| positioned atright angles to one another and fastened to a frame 52 on the cabinetwall. The position of the bearings and the roller is accuratelycontrolled by regulating the position of the bolts, by means of nutsthreaded thereon, in elongated slots in the frames.

The roller is positioned to cause the absorbent sheet thereon to firstengage the leading edge of the article, which is then traveling in asubstantially horizontal direction, just above the bottom of thearticle. Then as the article is further advanced by the conveyor, itsdirection of travel is changed towards the vertical which causes theentire lower edge portion of the article to be wiped across or rolledagainst the sheet of absorbent material. This action completely removesthe accumulated excess coating material. Because the articles are freeto move freely relative to the conveyor, due to the bearing supports,the pressure between the article and the absorbent material is not greatwith the result that all of the excess material is removed without thethickness of the desired coating at that portion of the 'article beingaffected.

Itis desirable to replace the absorbent material constantly assuccessive articles are delivered by the conveyor. To accomplish this,fresh absorbent material is delivered continuously to the roller by afeeding mechanism coordinated with the movement of the conveyor. In thismechanism the absorbent sheet material is supplied from a supply roll 53supported rotatably on' a pair of rotatable shafts 56 and 51 supportedin a bracket 58 on the back cabinet wall. One of these shafts is drivenby means of a chain 50 geared to one of conveyor sprockets. With thisconstruction fresh absorbent material is pulled' over the roller at alltimes that the conveyor is running.

After the articles are rolled against the wiper, they are carriedupwardly by the conveyor through a drying chamber 6| (Fig. 1). The hotair emitted from the ducts 45 is carried up into this drying chamber bythe action of the exhaust fan, and the position of the upper damper inthe exhaust chamber is set to insure the desired degree of drying orsetting of the coating material during passage of the article throughthis chamber.

From the drying chamber, the articles are carried downwardly by theconveyor through a cooling chamber 62. Cold air is supplied to thischamber from the front opening of the cabinet and its ow is regulated bythe position of the lower damper in the partition 22.

The operation of the apparatus is as follows: The articles are placed onthe hooks depending from the conveyor by the operator at the lowerportion of the front cabinet opening while the conveyor is in motion.The articles illustrated in the drawings are hung from a hole in theirupper corner, and other articles can be hung or clamped on the conveyorby any suitable means. From the loading position the articles arecarried to the coating container and immersed in the coating material.The wet articles are then carried over the drain board and into the zoneof the hot air jets. As previously explained, the hot air emitted fromthe front jets smooths the coating and removes the excess coating fromindentations and holes in the article, and air emitted from the sidejets accumulates all excess coating in abead depending from the lowercorner of the article. Next, the lower corner of the article is wipedacross or rolled against the absorbent sheet to remove this bead withoutaifecting the base coating. The articles are then carried successively ythrough the heating and cooling chambers, where the arranged coating israpidly dried and set, and

then delivered to the unloading position, at the top of the frontcabinet opening, where they are removed by the operator while theconveyor is in motion;

Due to the action of the hot air duct, wiper, forced drying andcooling,4 the resultant coating is smooth, uniform, unblemished anddurable and the articles are ready for immediate use without additionalnishing operations being `required. The process is rapid, involvesminimu'mhandling and is economical of coating material, with the resultthatan entirely satisfactory lcoating is applied on the article at lowcost.

'I'his apparatus can be used with various coat ing materials, such aslacquer, varnish, paint and the like, and is in general suitable for usewith those materials that are adapted to dip coating processes.

Also, various features of the invention can be used separately. Forexample, in certain instances, depending largely upon the configurationof the articles being coated, independent use of either the wipingmechanism or the hot air duct structure is advantageous.

It will, therefore, be apparent that modifications of the specificembodiment of the invention described herein are feasible and it is tobe un-l derstood that the invention is limited only by the scope of theappended claims.

What is claimed is:

1. In an apparatus for dip coating articles, a cabinet having an articletreating chamber therein, means for conveying the 'articles through thechamber, a container of coating material in the chamber for applyingcoatingmaterial on the articles by immersion, means for applying airpressure against the surfaces of the moving articles to move excesscoating material on the article to one portion of the article surface.and an absorbent material positioned in the path of the moving articlefor engaging the article and removing the accumulated excess coatingmaterial therefrom.

2. In an apparatus for dip coating articles having perforations therein,a walled cabinet with an elongated article treating chamber therein, aconveyor traversing said chamber for carrying the articles through thechamber, a container of coating material in the chamber for applyingcoating material on the articles by immersion, a plurality of shapedducts adjacent to said container for applying air pressureagainst thecoated articles to remove coating material from the article perforationsand move excess coating material to one portion of the article surface,an absorbent material in the path of the moving article for engaging thearticle and removing the excess coating material, and a heated area inthe chamber for drying the coating on the articles. Y

3. In an apparatus for dip coating articles having perforations andsurface indentations therein, a cabinet with an article treating chambertherein, a driven conveyor traversing said chamber for carrying articlessuspended therefrom through the chamber, a container of coating materialin the chamber for applying coating material-on the article byimmersion, a plurality of shaped ducts adjacent to the container forapplying air pressure against the surfaces of the coated articles toremove excess coating material from the article perforations 4andindentations and accumulating the excess coating material at the loweredge portion lof thesuspended article, an absorbent sheet adjacent tothe ducts for engaging the lower edge ofthe article and removing the Iaccumulated excess, coating, material therefrom as the articlesaremOi/,ed-by theconveyor, and means within the .chamber-,for drying theresidualy coatingon the articlesr,` l.

4. In an apparatusiordlp .coating articles having perforations andsurface indentations, a cabinet having an article treating-.chamber.there in, Va conveyor forl moving thezvarticlesthrough thechamber, a container-ofecoatingematerial at the bottom of thechamber@forpplying-oatlng material on the articles by. immersion,. a,series of shaped air ducts'positioned-adjacent?the path of thev coatedarticles,r said ductshaying a front wallwith jets therein fon-.emittingair against the surfaces Aof the, moving articles to remove coatingmaterial from. the articley .perforations, and side walls 4withjets,thereiri for applying air pressure against the .article surfaces andaccumulating the excess coating material at one portion-of the. articlesurface, an absorbent material positioned in the v path of the movingarticle forengaging the article'iand removing the accumulated excesscoating material therefrom, and a heated portion of said chamber fordrying the residual coating on the articles.

5. In an apparatus for dip coating articles, a

- cabinet having an article treating chamber therein, a conveyor formoving the articles through the chamber, means for driving the conveyor,a container of coating material at the bottom of the chamber forapplying coating material on the articles by immersion, means forapplying air pressure against the surfaces of the moving articles tomove excess coating material `on the article to one portion of thearticle surface, an absorbent material positioned in the path of themoving article for engaging the moving article and removingtheaccumulated excess coating material therefrom, and means coordinatedwith the conveyor drive for constantly supplying fresh absorbentmaterial to the position where the absorbent material engages the movingarticles.

6. In an apparatus for dip coating articles, a

' cabinet having an article treating chamber therein, a conveyor formoving the articles through the chamber, the articles being suspendedfrom the conveyor and hanging downwardly from the conveyor, a containerof coating material at the bottom of the chamber for applying coatingmaterial on the articles by immersion, means for applying air pressureagainst the surfaces of the moving, articles to move excess coatingmaterial on the article to the lower edge portion of the /suspendedlarticle, and a sheet of absorbent material positioned in the path ofthe movingarticle to remove the accumulated excess coating materialtherefrom, the absorbent sheet and direction of article travel beingcoordinated to cause the leading lower edge portion of the movingarticle to first engage the sheet and the complete lower edge portion ofthe article to be wiped against the sheet as the article is advanced bythe conveyor.-

7. In an apparatus for dip coating articles. a

cabinet having an elongated article treating chamber therein, a conveyorfor carrying the articles through the chamber, means for driving theconveyor, a container of coating material in the chamber for applyingcoating material on the articles by immersion, means for applying airpressure against the surfaces of the coated articles to accumulateexcess coating material on the article at one portion of the articlesurface, and means positioned in the path of the moving article andsubsequent to the accumulating means for engaging the article andremoving the acl cumulated excess coating material therefrom, said meanscomprising a roller adjacent to the article path. a sheet of absorbentmaterial wrapped over said roller for engaging the moving articles, afeed roll engaging the sheet for pulling the sheet over the roller, anda chain interconnecting the conveyor and the feed roll to cause thesheet to be advanced over the roller whenever the conveyor is in motion.

8. In an apparatus for dip coating" articles having perforations andsurface indentations therein, a walled cabinet having an elongated'article treating chamber therein, a conveyor traversing said chamberfor conducting articles suspended therefrom through the chamber, meansfor driving the conveyor, a container of coating material at the bottomportion of the cabinet for applying coating material on the articles byimmersion, a series of shaped hot air ducts positioned subsequent to thecontainer, said ducts having a front wall with vents therein foremitting air against the article surface to remove coating material fromthe article perforations, and side walls with a vent therein foremitting air to sweep excess coating material from the articleindentation and accumulate the excess coating material at the lowercorner of the article, an absorbent sheet positioned subsequent to theducts, said sheet being adapted to engage and absorb the accumulatedexcess coating material on the article, a feed roll engaging theabsorbent sheet, and a drive for said feed roll responsive to theconveyor drive for advancing the absorbent sheet whenever the conveyoris in motion.

9. In an apparatus for coating an article having perforations therein, achamber, means for moving the article through the chamber, means forapplying coating material on the article, means adjacent to the coatingmeans for applying air pressure against the article to remove coatingmaterial from the perforations and accumulate excess coating material atone portion of the article surface, an absorbent material in the path ofthe moving article for engaging the article and removing the excesscoating material therefrom, and means for drying the remaining coatingmaterial on the article.

GEORGE P. MCGRAW.

